Charles c



(No Model.)

O. O; TRAPP. REVOLVING CHAIR.

No. 434,743. Patented Aug. 19, 1890.

A I I i UNITED STATES PATENT OFFICE.

CHARLES c. TRAPP, OF PORT WASHINGTON, WISCONSIN, ASSIGNOR, BY MESNEASSIGNMENTS, TO JOHANNA TRAPP, OF SAME PLACE.

REVOLVING CHAIR.

srncmcnrron forming part of Letters Patent No. 434,743, dated August 19,1890.

Application filed April 24,1890. Serial No, 349,326. (No model.)

To all whom it may concern.-

Be it known that 1, CHARLES C. TRAPP, of Port \Vashington, in the countyof Ozaukee and State of Wisconsin, have invented new and usefulImprovements in Revolving Chairs; and I do hereby declare the followi'ngto be a full, clear, and exact description of said invention, referencebeing had to the accompanying drawings, and to the letters of referencemarked thereon, which form a part of this specification.

My invention in revolving chairs relates particularly to a device bywhich the chairseat may be raised or lowered by rotating it,

and by means of which device being properly set therefor the chair-seatmay be revolved freely without either raising or lowering it.

In the drawings, Figure l is aside elevation of my improved device,parts being in section to show interior construction. Fig. 2 is a topplan View of the device, parts being broken away to show interiorconstruction.

A metal head A is provided with sockets in its sides, inwhich the innerand upper ends of the legs B B are received and on which the head issupported, the legs being at the same time secured thereto. The metalhead is provided with a vertical central aperture through which thescrew-threaded spindle 0 moves freely, the aperture through the headbeing slightly larger than the greatest diameter of the screw. Thespindle is provided with a head D, on which the chair-seat is supported.A ring E, having a central aperture of greater diameter than thediameter of the screw of the spindle U, encircles the spindle'and restsand rotates on the top surface of the head A, but preferablyanti-friction balls F are inserted between the head A and ring 7 E inannular grooves therefor in the top of the head and in the bottom of thering E. These balls may or may not be used, as preferred, though theiruse greatly facilitates rotary movement of the ring E on the head A. Acap or guard G, having a central circular opening and an inwardly-projectin g flange G encircles the base of the ring E and is securedpermanently to the head A conveniently by means of screws H H passingthrough the guard and through apertures therefor in flanges of the headand turning into the legs B B. The flange G fits about the ring E justabove flange E, projecting outwardly from the base of the ring E. Bythis construction the ring E is retained movably in place near to oragainst the head A, on which it rotates freely. A split or two-partsleeve-nut I, in which the spindle C turns by its screw-thread, islocated loosely within the ring E, the nut being provided at its topedge with a laterally-projecting flange I, which rests on the top of thering E and supports the nut movably therein. A set-screw K, providedwith a small hand-wheel K, turns through the ring E against the splitnut I, and is adapted by being turned firmly against. the nut to claspthe ring, the nut, and the spindle rigidly together.

In operation when the set-screw K is turned firmly against the splitsleeve-nut I so as to clasp the ring, the sleeve-nut, and the spindlerigidly together, the chair-seat will then revolve freely on the bearingformed by the ring E resting on the head A, either with or without theinterposed balls F, and when the setscrew K is turned out from its seatsufficiently to release the split nut I from clamping the spindlerigidly to the ring E, the spindle will, on rotation thereof byrevolving the chairseat or otherwise, turn freelyin the sleeve-nut,thereby raising or lowering the chair-scat by the rotation of thescrew-threaded spindle in the nut. hen rotating the spindle in the nutI, it may be necessary to hold the ring E against rotation, which can beconveniently done by grasping the wheel K with one hand while with theother hand the seat can be rotated.

The sleeve -nut, the spindle, and the ring are to be clamped togetherrigidly at all times except only when the chair-seat is to be raised orlowered by turning the spindle in the nut.

WVhat I claim as new,and desire to secure by Letters Patent, is

1. In a revolving chair having a head, as A, provided with a centralvertical aperture and with a spindle C affixed to the chair-seat andarranged to move freely in the aperture in the head,the combination of aring E, a split sleevenut I, and a set-screw turning through the ringagainst the split nut, substantially as described.

2. In a revolving chair, the combination, with a metal head supported onthe legs and a screw-threaded spindle affixed to the seat and passingmovably through the head independently of its screw-thread, of aring, asE,

about the spindle, a guard, as G, whereby the ring is held rotatablynear to the head, a split nut, as I, about the spindle within the ring,and a set-screw turning through the ring against the nut, substantiallyas described.

3. In a revolving chair having a metal head supported on the legs, whichhead is provided with a vertical aperture through which a screwthreadedspindle carrying a seat thereon passesmovably independently of itsscrew- In testimony whereof I aifix my signature in the presence of twowitnesses.

CHARLES (J. TRAPP.

Witnesses:

H. L. Con, .T. J. CRAMER.

